Air conditioners and the like are equipped for example with a semiconductor circuit board for controlling the operations of the air conditioners. A conventional semiconductor circuit board is formed by an integrated circuit group, a control circuit thereof, a power circuit and the like arranged on the same board. The integrated circuit group includes for example a high-speed switching element, a transmitter/receiver circuit and others. The control circuit includes for example a microprocessor and others, and is operative to control the integrated circuit group. The power circuit is operative to supply power to the integrated circuit group.
Patent publication 1 discloses a technique for simulating a radiation noise. Non-patent publication 1 introduces a technique for reducing a noise generated by a power source by using an inductor such as ferrite beads or a coil, and a by-pass capacitor. Non-patent publication 2 introduces a technique for reducing a noise generated by an electronic device formed by a substrate with a stacked multilayer structure.    Patent Publication 1: Japanese Patent Application Laid-Open No. 6-309420 (1994)    Non-Patent Publication 1: “Transistor Technology” published by CQ Publishing Co., Ltd., October 2001 issue, p. 202    Non-Patent Publication 2: “101 Qs and As about Noise Countermeasures” written by Seiichi Miyazaki, published by Integrated Systems Institute, pp. 88-89